Regeneron Pharmaceuticals Faces Class Action Over Trial Results
A class action lawsuit alleges Regeneron Pharmaceuticals misled investors about a late-stage melanoma trial involving Fianlimab and Libtayo. Investors suffered losses as details surrounding the lawsuit emerged.
Regeneron Pharmaceuticals (NASDAQ: REGN) is facing a securities class action lawsuit alleging that the company misled investors regarding the prospects of its Phase 3 clinical trial for advanced melanoma.
The lawsuit, filed on behalf of investors who purchased or acquired Regeneron securities between August 1, 2025, and May 15, 2026, claims the company failed to disclose material information concerning the trial's viability. Investors who incurred losses during this period may be eligible to participate in recovering those losses, according to law firm Robbins LLP.
According to the complaint, Regeneron provided positive statements about the Fianlimab-Libtayo trial while allegedly failing to disclose flaws in the study's statistical assumptions and that the treatment arm was not showing meaningful differentiation from standard therapies. The complaint suggests these omissions artificially inflated the company's stock price.
Disclosure of issues began on April 29, 2026, when Regeneron announced changes to the patient analysis, causing its stock price to drop. The situation intensified on May 15, 2026, when Regeneron announced that the trial failed to meet its primary endpoint of improving progression-free survival, leading to a further stock price decline of approximately 10%.
The lawsuit aims to recover damages for investors who purchased Regeneron securities during the specified class period. The deadline for investors to seek appointment as lead plaintiff is September 14, 2026. Interested parties are advised to contact Robbins LLP for more information.